Use of digital household appliances has been increased recently. It has developed such that Digital household appliances, such as digital television, HDD recorder, etc. have a communication function and connected to a network, via which varies services can be enjoyed and various function can be executed.
Meanwhile, this requires such digital household appliances to have many functions therein, thereby adding more demands in developing digital household appliances with more variety. More specifically, what are demanded are: avoiding an increase in steps necessary for developing or testing the digital household appliances; reducing loss due to reworking, quickly changing functions of the apparatus in response to the fast-changing market; etc.
Under these circumstances, a system to develop digital household appliances effectively has been sought for. Moreover, it is desirable to provide a system by which a digital household appliance after shipment to the market can be updated easily with a program therefor by a user who has purchased the apparatus.
Changing the function of the digital household appliance can be done by downloading a program as in the use of Java (Registered Trademark) for portable phones, or automatically updating the program in the digital household apparatus (for example, HDD recorder) (e.g., see Known Art 1/Known Art 2).
[Known Art 1]
Overview on I-Appli (Registered Trademark)
[Searched on Jul. 31, 2006] on the Internet <URL:
http://www.nttdocomo.co.jp/service/imode/make/content/iappli/about/index.html>
[Known Art 2]
V apuli
[Searched on Jul. 31, 2006] on the Internet <URL:
http://developers.vodafone.jp/dp/tech_svc/java/>
However, it is a problem that it is not easy to change the function of a digital household apparatus by changing a program thereof.
This problem is explained below more specifically. In the methods described in Known Art 1 and 2, a digital household apparatus is provided with an Internet browser, which is software for viewing data obtained from an external apparatus. The digital household apparatus uses the function of the Internet browser so as to acquire and display data distributed through the Internet. By changing the distributed data, it is possible to change contents of display displayed by the digital household apparatus.
However, to change the function that the digital household apparatus carries out is not as easy as changing the contents of the display. This is because the function of the Internet browser is prescribed by the program stored in a storage of the digital household apparatus. So, the changing the function of the Internet browser of the digital household apparatus requires that a distributor of the data update the program and distribute the updated program to the digital household apparatus.
The distributors face a problem of a large development cost due to the need of frequent updating a program in order to change the function. Moreover, the user of the digital household apparatus should acquire a program of a new version from the distributor every time the function is updated. This is not user friendly.
To make the matter worse, the system for updating the function of the digital household apparatus has not been well established compared with the system for updating the function of personal computes (PC), as described above. Most of the digital household apparatus such as television or portable telephone are computer-embedded apparatuses whose functions are realized by a program that is written in a non-volatile storage device such as ROM (read only memory) etc. in a non-rewritable manner.
Therefore, to exchange the ROM is only way to update the function of the digital household apparatus that has been shipped to the market. However, this method is not realistic because it is not easy for everybody to exchange the ROM and it is too costly to do so.
Note that this problem is not only incidental to the digital household apparatus, but also to any computer-embedded apparatus, like the digital household, whose functions are realized by a program having been written in a ROM at its production.